Travel limiting device for the travelling block of hoisting installations provided with pneumatic controls



Jan. 23, 1968 D. POMPILIU ETAL 3,365,175

TRAVEL LIMITING DEVICE FOR THE TRAVELLING BLOCK OF HOISTINGINSTALLATIONS PROVIDED WITH PNEUMATIC CONTROLS Filed March 24, 1965 2Sheets-Sheet 1 I In ven tors.-

ram -.1. nummescu TURICU ocmvmm TRmAN fh ir Afforney 3,365175 CK OF Jan.23, 1968 D. POMPILIU ETAL TRAVEL LIMITING DEVICE FOR THE TRAVELLING BLOHOISTING INSTALLATIONS PROVID ED WITH I PNEUMATIC CONTROLS Filed March24, 1965 2 Sheets-Sheet 2 In ven tors.- Porhpil-iu-DUMITRESCU TURICUocrqwlm TRmAN 6,; Q {hei Affomey United States Patent 3,365,175 TRAVELLIMITING DEVICE FOR THE TRAVEL- LING BLOCK OF HOISTING INSTALLATIONSPROVIDED WITH PNEUMATIC CONTROLS Dumitrescu Pompiliu, B-dul Republicii55, and Octavian Traian Turicu, Str. Bach Bloc 8/5, both of Bucharest,Rumania Filed Mar. 24, 1965, Ser. No. 442,465 Claims priority,application Rumania, Mar. 31, 1964, 47,741 4 Claims. (Cl. 254-173) Thisinvention relates to a limiting device for the travel of the travellingblock used in conjunction with drilling rigs, hoists and similarinstallations.

A travel limiting device for the travelling block of draw works isalready known in the art. In this known device the stopping operation iseffectuated by means of an air valve (mounted on the derrick floor) andactuated directly by the travelling block, by means of a cable line.

This known device presents the disadvantage of having the control valvemounted on the derrick floor and close to the rotary table of thederrick, which causes it to be exposed to bad weather and to thecorrosive action of the water and drilling fluid. Since this device isidle most of the time, the valve can easily become stuck. Thus,conditions can occur when the valve counterweight is not great enough toactuate a stuck valve of the device.

The connecting cable line being quite thin, it has been found to beprone to be carried away by the drilling line, which causes it to enterbetween the travelling block sheaves and wire rope, thus damaging thedevice.

The adjustment of the limit height, for the travelling block travel, isdifiicult, because a changing of the attachment point of the cable lineto the derrick braces is required, this operation can only be carriedout at a i great height and with great difiiculties.

There is also known another travelling block travel limiting device,which can be mounted in the drilling rig derricks. This known device hasa safety valve attached to the draw works, and is actuated-at apreselected moment-by the layers of drilling line spooled onto thehoisting drum.

The safety valve of this known device stops the travelling lock at asafe level in the derrick, by actuating the hoisting drum brake andsimultaneously therewith disengaging the power groups from the drawworks.

This known device presents the shortcoming that in case of an irregularspooling of the drilling line which can happen quite frequently, thelayers of drilling line can get interpenetrated (wraps belonging to theupper layer can get inbetween the lower layer wraps) and, consequently,the device can stop the travelling block too early, or too late, thelatter case being quite dangerous.

It is a general object of this invention to eliminate the abovementioned disadvantages by having the entire travelling block travellimiting device mounted in a completely enclosed space inside the drawworks, and having the device actuated directly by the draw workshoisting drum.

This invention relates to a travel limiting device for travelling blocksbelonging to hoisting installations and comprises a threaded rod with anut mounted thereon which is driven by the hoisting drum shaft; apneumatic stop valve which actuates a control relay, by means of which,and depending on the nut position on the threaded rod, the air passageto the hoisting drum clutch is opened or closed, and concomitantlytherewith the hoisting drum is accordingly started or stopped. Thishoisting drum stoppage is effectuated by means of the pneumatic drumbrake, which is activated by means of a switch valve and a brake releasevalve which brings out of action the hoisting drum and respectivelystops automatically the travel- "ice ling block at a safe heightestablished by an initial adjustment. This adjustment consists ofconveniently rotating the aforementioned threaded rod until the nut,which is moving on it, trips the pneumatic stop valve at the desiredmoment.

Two illustrative embodiments of a machine constructed in accordance withthe invention, together with additional objects and advantages thereof,will be best understood from the following description of specificembodiments, when read in connection with the accompanying drawing, inwhich:

FIG. 1 is a schematic illustration of a travelling block travel limitingdevice according to this invention, attached to a. drilling rig, withoutan automatic hoisting drum stop FIG. 2 is a schematic illustration ofthe same device, as illustrated in FIG. 1, but with an automatichoisting drum stop.

Referring now specifically to the drawing, two examples of the device ofthis invention are described.

Example I The device, according to the invention and illustrated in FIG.1 comprises a driving wheel 1, coaxially attached to the hoisting drumshaft 2, which in turn drives a threaded rod 5 by means of a chain 3, asprocket wheel 4 and a transmission arrangement 6 (bevel gear, helicalgear, worm gear, etc., transmission).

The sprocket wheel 4 is secured to its supporting shaft by means of acone, which is used for adjusting the device in accordance with thenumber of travelling block lines, respectively in accordance with themaximum allowable height. The structure of the adjusting cone is standard and, consequently, well known in the art and has not beenillustrated in detail.

The installation includes also a nut 7 which can be shifted, withoutrotating it, along the threaded rod 5. A pneumatic stop valve A, whichis actuated by a pivotable control lever 8 having a roller at its freeend, and a main relay B, both of which are connected together by meansof the air lines 9 and are also connected to the main compressed airsystem 10 for the device. The pneumatic stop valve A comprises a housing11 having a vent opening at one end thereof, a valve member 12 axiallymovably mounted therein, a spring 13, urging the valve member 12 into aclosed position, and a valve member 14 with a control rod, whichcooperates with the lever 8.

The housing 11 is provided with a compressed air supply inlet orifice 15and an outlet orifice 16, which allows the air to pass towards the mainrelay B.

The main relay B comprises a housing 17 composed of three compartmentsand a lid 18. A rubber diaphragm 19 is mounted between the lid 18 andthe lower ends of the outer walls of the housing 17. The diaphragm 19 isurged upwardly by a coil spring 20.

Inside the housing 17 there is mounted a valve member 22 whichcooperates with the valve seat member 21 and the valve seat 21a. A valveclosing spring 23 acts on the valve member 22.

The housing 17 is provided with an orifice 24 through which the air isentering from the stop valve A. An orifice 25 in the wall of housing 17serves as an inlet for the air supply, and an orifice 26 in the wall ofhousing 17 provides an outlet for the air to pass towards the clutch(not shown). An orifice 27 in the housing 17 permits a bleeding off ofthe air from the clutch. The compressed air passing through opening 27is released into the atmosphere.

The device of this invention operates as follows:

In the first place the device has to be adjusted and for this purpose,the travelling block is brought to the upper limit position, thesprocket wheel 4 is loosened and the shaft is rotated by means of awrench (not shown) 3 until the nut 7-which is shifted along the threadedrod 5 by means of the drive 6strikes the control lever 8, therebytripping the device. in this position, the sprocket wheel 4 is againfastened onto its corresponding supporting shaft by means of its lockingcone and lock nut.

After this adjustment has been made as long as the drilling rig isworking without the travelling block exceeding the safe height, the nut7 shifts along the rod 5 in one direction or another without strikingthe control lever 8; the compressed air from the main line 11 can notpass towards the relay B, through the orifice 24, because the valvemember 12 from the stop valve A is in its closed position, but it canpass through the relay B orifice 25, and because the valve member 22 isin its open position, the air can pass freely through the orifice 26towards the reverser or hoisting drum clutch (not shown) and,consequently, the drum is placed in its working position.

When the nut 7, belonging to the travel limiting device, strikes thelever 8, however, the valve member 14 from the stop valve A is pushedtoward the interior of the housing 11, thus closing the air release tothe atmosphere, and opening the valve member 12. Now the compressed aircan pass from the orifice 15 towards the outlet orifice 16, and fromthere through the orifice 24 to the relay B.

Thus the left plate 12a of valve member 12 closes the passage for thecompressed air towards the space in communication with the orifice 16.It should also be noted that during the operation of the device theorifice 15 never comes directly into communication with the atmosphere,which would result in unnecessary losses of compressed air.

While the stop valve A is in the aforedescribed position the orifice 16communicates with the atmosphere via the space between the right handplate 12b of the valve member 12 and through the central passage 14a ofthe valve member 14 and through the vent opening 11a at the right endwall of the valve housing 11.

When the valve member 14 is pushed inwards, it meets first the righthand plate 12b of valve member 12 thereby closing the communicationbetween the orifice 16 and the atmosphere. Continuing its inward stroke,valve member 14 pushes valve member 12 toward the left thereby liftingthe left hand plate 12a from its valve seat and placing orifice 15 incommunication with orifice 16.

On the other hand when the valve member 14 is again pushed outwardly bythe springs 12c and 13, the valve member 12 follows, due to the actionof the spring 13, thereby cutting off the connection between theorifices 15 and 16 by repositioning the plate 12a on its valve seat. Thevalve member 14,, which continues its outward movement, can no longer befollowed by the valve member 12 and, consequently, the right hand plate12b lifts off the opening for the passage 14a thereby establishing acommunication between the orifice 16 and the atmosphere. The main relayB works as follows when the stop valve A assumes the aforedescribed twopositions:

(a) When the orifice 24 is placed in communication with the atmosphereby the stop valve A (the component parts of the relay B and stop valve Aare in the positions illustrated in FIG. 1) the coil spring 20 acts onthe valve seat 21 member via the membrane 19 and urges it to the upperlimit of its stroke. The lower plate 22a of the valve member 22 comes torest on the valve seat member 21, whereas the upper plate 22b is raisedfrom its valve seat 21a. When the component parts of the relay B are inthe aforcdescribed position the orifice 26 places the compressed air viathe orifice 25 in communication with the pneumatic clutch of thedrawworks (not illustrated) and closes at the same time thecommunications of the orifice 26 with the atmosphere.

(b) When the orifice 24 is placed in communication with the source ofcompressed air via the orifices 15 and 16 the pressure formed in thelower chamber of the relay B causes the membrane 19 to deflectdownwardly thereby entraining the valve seat member 21 to which it isconnected. The valve member 22, due to the action of the spring 23,follows the valve seat member 21 until its upper plate 22b comes to reston the valve seat 21a. This causes a closing of the flow path fromorifice 25 to orifice 26. Since the valve seat member 21 has a longerstroke than the valve member 22, the valve seat member 21 continues itsdownward stroke, thereby disengaging itself from the lower plate 22a,and by means of the channels disposed in its body places the orifice 26in communication with the atmosphere. In this manner the compressed airin the clutch is dissipated and the clutch disengages itself.

When the pressure at the orifice 24 is discontinued (when the orifice 16is in communication with the atmosphere i.e. the position illustrated inFIG. 1), the relay B returns to the position illustrated in FIG. 1.

It should be noted that both the relay B and the stop valve A operatesimilarly in principle i.e. first the flow path between the orifice 25and the atmosphere is closed and only afterwards the flow path betweenthe source of compressed air and the orifice 26 is opened. This is dueto the similar operation of the valve member pairs 12, 14 and 21, 22.

Consequently, the valve member 22 closes the entrance of the compressedair towards the clutches (not shown); the air from the drum and reverserclutches is bled off into the atmosphere through the central orifice ofthe valve seat member 21 and through the bleeder orifice 27, therebyuncouples the hoisting drum from its drive. Simultaneously with the drumuncoupling the travelling block is stopped. When through the relay B,the entire drilling rig is fed with compressed air, the above mentionedsafety device uncouples all the rig clutches including those providedfor the engines, and in this case it insures the complete protection ofthe rig even in the case when due to diverse reasons, the drawworks andreverser clutches got stuck.

Example II The device according to this invention illustrated in FIG. 2comprises a driving wheel 28 attached to a hoisting drum shaft 29, whichin its turn is driving by means of a chain 30, a sprocket wheel 31,which is fastened onto its supporting shaft by means of a cone which isused for the adjustment of the device. The adjustment is made inaccordance with the number of cable lines on the travelling block,respectively in accordance with the maximum height allowed for thetravelling block travel. The structure of the adjusting cone is standardand consequently well known in the art and has not been illustrated indetail.

Through a gear 32 (which can be cylindrical, bevel, helical or wormgear) there is driven the gear wheel 33 which is axially secured to thethreaded rod 34.

The device includes also a nut 35, which can be longi tudinallyshifted-without rotatingalong a threaded rod 34. A pneumatic stop valveC is actuated in its turn by a control lever 36 having a roller at itsfree end. The device further includes main relay D, a releasing valve E,a switch valve F, a hoisting drum control valve G and a control valve Hfor the hoisting drum pneumatic brake, all of which form part of thedevice and are operatively connected to each other in an arrangementthat will be set forth below.

The pneumatic stop valve C comprises a valve body 37, a control andunload valve member 38 axially movably mounted in the valve body 37. Aspring 39 is mounted inside a cavity of the valve body 37.

A stop valve member 40 actuated by a valve spring 41 is mounted inside avalve seat member 42. A threaded guide member cover 43 is axiallymounted in the lower end of the valve body 37 and seals a compartmentsituated therein and serves also to guide the valve member 40. The valvebody 37 is provided with an inlet orifice 44 for compressed air feeding,and an orifice 45 for letting air pass towards the main relay D.

The main relay D comprises a valve housing 46, a valve member 47 axiallymovably mounted therein, a double valve seat 48 mounted inside thehousing 46. A coil spring 49 urges the valve member 47 downwardly into aclosed position. A threaded lid 50 having a central bore is threadablymounted into the upper end of the housing 46.

The housing is provided with an orifice 51 for air inlet from the stopvalve C; an orifice 52 for compressed air feeding from the maincompressed air feeder line 67, an orifice 53 for permitting air to passtowards the hoisting drum clutch and the aforementioned orifice 54 forair bleed-off into the atmosphere.

The release valve E comprises a valve cylinder 55, in which there isaxially movably mounted a distribution piston 56. A button lid 57 issecured to the lower end of the piston 56. A reset spring 58 urges thebutton lid 57 downwardly.

The valve cylinder is provided with an orifice 59 which acts as an airinlet for air coming from the switch valve F; an orifice 60 which actsas an air outlet for air passing towards a pneumatic brake for thehoisting drum; and an orifice 61 for bleeding ofi the air into theatmosphere.

The switch valve F is composed of a body 62 and a switch piston 63axially movably mounted therein. The body 62 is provided with theorifices 64, 65 and 66, the functions of which will be set forth below.

The stop valve C, the main relay D, the release valve E, the switchvalve F and the control valves G and H are connected together by aseries of lines through which the compressed air is effectuated from themain pipe line 67.

The device operates as follows:

In the first place, the adjustment of the device is required to becarried out, and for this purpose, the travelling block is brought toits upper limit position; the sprocket wheel 31 is loosened and theshaft 34 is turned by means of a wrench (not shown), until the nut 35strikes the control lever 36, thereby tripping the device.

In this position, the sprocket wheel 31 is fastened onto itscorresponding shaft, by means of the locking cone and lock nut.

After this adjustment has been made as long as the drilling rig isworking without the travelling block exceeding the safe height, the nut35 is shifting, in one direction or another, along the threaded rod 34without striking the control lever 36; while the control lever 36 is nottripped the compressed air from the main line 67 can not pass towardsthe relay D through the orifice 51, because the valve member 40 of thestop valve C remains in its closed position; however, the compressed aircan pass during this time through the orifice 52 and relay D, and fromthere through the double valve seat 48 and orifice 53, the air thenbeing further directed towards the hoisting drum clutch, through theintermediary control valve G, thus placing the drum in its workingposition.

When the nut 35 strikes the lever 36, the valve member 38 of the stopvalve is pushed towards the interior by the lever 36, thus shutting offthe air release into the atmosphere of air passing along valve member38. Concomitantly therewith the valve member 40 is opened and thecompressed air coming from the orifice 44 now passes through theorifices 45 and 51 towards the relay D. Consequently, the valve member47 shuts off the air entering from the main line 67 (through orifice 52)by moving upward the valve member 47 and seating it on the lower seat ofthe double valve seat 48.

Simultaneously therewith, the drum 29 is uncoupled because the air fromthe clutch is bled off into the atmosphere via the valve G, the orifice53, the upper 6 seat of the double valve seat 48 and finally through theorifice 54.

Simultaneously with the hoisting drum uncoupling, there takes place thedrum automatic braking-respectively travelling block stopping, asfollows:

The air which passes towards the orifice 51, enters the switch valve Fthrough orifice 64 and pushes the rubber piston 63 towards orifice 65which is thereby closed. The air thereafter passes through orifice 59towards the unloading valve E, and from there through orifice 60 towardsthe pneumatic brake servomotor K, which causes by means of a leverarrangement to actuate a brake for braking the drum 29.

The restarting of the hoisting drum 29 requires the following operationsto be performed:

The unloading valve E button is pushed, thereby blocking orifice 59, andthe air from the hoisting drum pneumatic brake can then be bled off intothe atmosphere, passing first through orifice 60, then around thedistribution piston 56 annular space and finally through the atmospherethrough orifice 61.

Afterwards the drum can be unwound (the drum brake being manuallycontrolled) until the contact between the nut 35 and control lever 36 isbroken. In this position, the stop valve C, by the action of spring 41,closes the air entrance towards the main relay D (the valve member 40 isseated on its seat 42) opening at the same time to the atmosphere thecompressed air in the air line 68, through the orifice 45 and the valvemember 38 central exhaust port.

Consequently, the valve member 47 of the main relay D returns to itsinitial position due to the action of the coil spring 49, and thehoisting drum clutch can be fed again with the compressed air from themain line, which, of course, passes again through the control valve G.

From the moment the pipe line 68 is put in communication with theatmosphere, the manual pressure on the button 57 is interrupted and thepneumatic pressure on the brake for the hoist drum is, consequently,also interrupted and, consequently, the pneumatic braking of thehoisting drum by means of the control valve E becomes normal (when thevalve H is opened, the compressed air pushes the piston 63 towards theorifice 64, closing it and the compressed air now passes through theorifice 59, through the piston 56 annular space and orifice 60, wherebyit brakes the drum at a rate preselected by the operator) The device ofthis invention presents the following advantages:

It has a greater sensitivity and, consequently, it instantaneouslyuncouples and brakes the hoisting drum, thereby automatically stoppingthe travelling block at a predetermined safe level;

It renders greater safety during operation of the hoisting installation;

It is easily adjusted, due to the fact that it is connected to the drawworks.

Although this invention has been illustrated and described withreference to two preferred embodiments thereof, it is to be understoodthat it is in no way limited to the details of such embodiments but iscapable of numerous modifications within the scope of the appendedclaims.

What we claim is:

1. In a hoisting installation of the character described having apneumatic source of power, a travel limiting mechanism including a drumfor spooling a cable thereon which is operatively mounted in saidinstallation; a pneumatically actuated clutch operatively connected tosaid drum; stop valve means having an inlet and outlet; a first valvemember reciprocally mounted in said stop valve means and responsive torotation of said drum; pneumatic relay Valve means having a first inlet,a first outlet, a second inlet, and a second outlet; the first inlet ofsaid pneumatic relay valve means being in communication with the outletof said stop valve means, the inlet of said stop valve means being incommunication with said pneumatic source of power and the first outletof said pneumatic relay valve means being in communication with saidpneumatically actuated clutch and with said second inlet; said secondinlet being in communication with said pneumatic source of power; asecond valve member reciprocally mounted in said relay valve means; saidfirst and second valve members being adapted to respectively cooperatewith the inlets and outlets of said stop valve means and pneumatic relayvalve means 50 that when said first valve member is acted on by saiddrum it moves in said stop valve means from a position wherein the inletand outlet thereof are not in communication with each other to aposition wherein the inlet and outlet thereof are in communication witheach other, thereby placing the first inlet of said relay valve means incommunication with said pneumatic source of power, via the inlet andoutlet of said stop valve means, said pneumatic source of power therebyacting on said second valve member and operatively moving the latterfrom a position in which the first outlet thereof is in communicationwith said pneumatic source of power via the second inlet thereof to aposition wherein said first outlet is in communication with said secondoutlet.

2. In a hoisting installation of the character described, having apneumatic source of power, a travel limiting mechanism as set forth inclaim 1, including pneumatic brake means operatively connected to saiddrum, a distributor valve pneumatically connected on the one hand tosaid pneumatic source of power and further being pneumatically connectedto said stop valve means and said pneumatic brake, whereby when saidstop valve means is actuated it also effects a pneumatic communicationof said pneumatic brake with said pneumatic source of power via saiddistributor valve, thereby activating said pneumatic brake and brakingthe movement of said drum.

3 In a hoisting installation of the character described having apneumatic source of power, a travel limiting mechanism as set forth inclaim 2, including means operatively connecting said drum to said firstvalve member, said means comprising adjustable gear means operativelyconnecting said drum, a lever pivotally mounted in said travel mechanismadjacent to said pneumatic stop valve means, said lever being adapted tobe tripped by said first valve member, a threaded rod rotatably mountedadja: cent to said lever and being operatively connected to saidadjustable gear means so as to be rotated by them, a nut threadablymounted on said rod and adapted to move to and fro on said rod dependingon the direction of rotation thereof, said nut being adapted to tripsaid lever when said drum has passed said preselected limit position.

4. In a hoisting installation of the character described having apneumatic source of power, a travel limiting mechanism as set forth inclaim 3, including a changeover valve mounted on the one hand, betweensaid pneumatic source of power and said distributor valve and beingpneumatically connected thereto, and on the other hand, between saidstop valve means and said distributor valve and being pneumaticallyconnected thereto.

References Cited UNITED STATES PATENTS 774,767 11/1904 Lyon. 963,3847/1910 Ogle. 1,452,964 4/1923 Falkenau. 2,376,019 5/1945 Thomas.2,502,710 4/1950 Duncan 254173 2,656,027 10/ 1953 Crookston.

SAMUEL F. COLEMAN, Primary Examiner.

1. IN A HOISTING INSTALLATION OF THE CHARACTER DESCRIBED HAVING APNEUMATIC SOURCE OF POWER, A TRAVEL LIMITING MECHANISM INCLUDING A DRUMFOR SPOOLING A CABLE THEREON WHICH IS OPERATIVELY MOUNTED IN SAIDINSTALLATION; A PNEUMATICALLY ACTUATED CLUTCH OPERATIVELY CONNECTED TOSAID DRUM; STOP VALVE MEANS HAVING AN INLET AND OUTLET; A FIRST VALVEMEMBER RECIPROCALLY MOUNTED IN SAID STOP VALVE MEANS AND RESPONSIVE TOROTATION OF SAID DRUM; PNEUMATIC RELAY VALVE MEANS HAVING A FIRST INLET,A FIRST OUTLET, A SECOND INLET, AND A SECOND OUTLET; THE FIRST INLET OFSAID PNEUMATIC RELAY VALVE MEANS BEING IN COMMUNICATION WITH THE OUTLETOF SAID STOP VALVE MEANS, THE INLET OF SAID STOP VALVE MEANS BEING INCOMMUNICATION WITH SAID PNEUMATIC SOURCE OF POWER AND THE FIRST OUTLETOF SAID PNEUMATIC RELAY VALVE MEANS BEING IN COMMUNICATION WITH SAIDPNEUMATICALLY ACTUATED CLUTCH AND WITH SAID SECOND INLET; SAID SECONDINLET BEING IN COMMUNICATION WITH SAID PNEUMATIC SOURCE OF POWER; ASECOND VALVE MEMBER RECIPROCALLY MOUNTED IN SAID RELAY VALVE MEANS; SAIDFIRST AND SECOND VALVE MEMBERS BEING ADAPTED TO RESPECTIVELY COOPERATEWITH THE INLETS AND OUTLETS OF SAID STOP VALVE MEANS AND PNEUMATIC RELAYVALVE MEANS SO THAT WHEN SAID FIRST VALVE MEMBER IS ACTED ON BY SAIDDRUM IT MOVES IN SAID STOP VALVE MEANS FROM A POSITION WHEREIN THE INLETAND OUTLET THEREOF ARE NOT IN COMMUNICATION WITH EACH OTHER TO APOSITION WHEREIN THE INLET AND OUTLET THEREOF ARE IN COMMUNICATION WITHEACH OTHER, THEREBY PLACING THE FIRST INLET OF SAID RELAY VALVE MEANSINCOMMUNCIATION WITH SAID PNEUMATIC SOURCE OF POWER, VIA THE INLET ANDOUTLET OF SAID STOP VALVE MEANS, SAID PNEUMATIC SOURCE OF POWER THEREBYACTING ON SAID SECOND VALVE MEMBER AND OPERATIVELY MOVING THE LATTERFROM A POSITION IN WHICH THE FIRST OUTLET THEREOF IS IN COMMUNICATIONWITH SAID PNEUMATIC SOURCE OF POWER VIA THE SECOND INLET THEREOF TO APOSITION WHEREIN SAID FIRST OUTLET IS IN COMMUNICATION WITH SAID SECONDOUTLET.